Embodiments of the disclosure pertain to an optical or optoelectronic transceiver comprising an optical or optoelectronic receiver, an optical or optoelectronic transmitter, a plurality of electrical devices, a housing, and a heat sink having a non-planar surface. The optical or optoelectronic receiver includes a receiver optical subassembly (ROSA). The optical or optoelectronic transmitter includes a transmitter optical subassembly (TOSA). The electrical devices are configured to provide or control one or more functions of the optical or optoelectronic receiver and the optical or optoelectronic transmitter. The housing is over and/or enclosing the optical or optoelectronic receiver and the optical or optoelectronic transmitter. The housing includes a first section and a second section, and is configured to (a) be removably insertable into a cage or socket of a host device and (b) position the first section of the housing outside the cage or socket when the housing is inserted in the cage or socket. The heat sink is over or adjacent to the first section of the housing and is in thermal contact with the housing.